Conventional architectural lighting systems such as office lighting systems are often managed by dedicated lighting control hardware. These systems typically include a central controller that is hardwired to remote photosensors, wall switches, and/or occupancy sensors for input data, and to relay panels or dimmer racks for luminaire control. The controller is usually responsible for dimming and switching the luminaires in response to input signals from daylight sensors and occupancy sensors, as well as scheduled events. The controller is typically programmed by means of a dedicated control panel.
These conventional lighting systems have a number of disadvantages. For example, the remote photosensors, wall switches, and occupancy sensors must be hardwired to the controller using low-voltage wiring routed through dedicated conduits. This represents a significant expense during building construction.
Another potential disadvantage of the conventional systems is that the sensors, e.g., photosensors or occupancy sensors, are usually fixed to the ceiling or the wall. Fixed sensors may have drawbacks in open offices where cubicle layouts often change in response to building tenant requirements. Thus, fixed sensor locations which are optimal for one configuration of cubicles and office furniture may be poor or even inoperable for other configurations.
Another potential disadvantage of the conventional systems is that the fixed sensors typically do not detect the lighting that is directly applied to the area occupied or operated in by the user. While the user is operating, for example, the display of a computer, a ceiling-mounted or wall-mounted sensor typically detects the light at the location of the sensor, which is only indirectly related to the lighting directly applied to the area around the display.
Yet another potential disadvantage of the conventional systems is that the central controllers are often located in service rooms or closets and are thus inaccessible to most office workers. Even when the controllers are accessible, their proprietary user interfaces are often difficult to understand and use. Consequently, the lighting system is usually programmed only once during system commissioning and afterwards it is not re-programmed, even when the layout of the office, or its lighting requirements, change.
Further, most central controllers are capable of storing events, such as weekly and yearly schedules, that turn off the luminaires on weekends and holidays. However, due to the difficulty of programming the conventional controllers, their event scheduling capabilities are usually underutilized. As a result, the luminaires are often turned on when they are not required, thus wasting energy.